Antioxidants:
An Antidote to Aging?
Reprinted from
Food Insight
November/December 1993
Mom always said,
"Eat your fruits and vegetables, they'll
help you grow big and strong." Although dietary
recommendations have changed over the years, this
is one bit of advice even Father Time can't ignore.
According to recent
studies, antioxidant vitamins in produce and other
foods may actually represent a modern-day "Fountain
of Youth." Evidence suggests that vitamins
C and E, and beta carotene, a precursor to vitamin
A, may reduce the risk of some forms of cancer,
heart disease, strokes, cataracts, as well as
slow the aging process.
How do these compounds
work and how far are scientists willing to go
in touting their health benefits?

Antioxidants
at Work
Although oxygen is
vital to life, scientists are also finding this
essential element may contribute to human aging
and illness.
When oxygen is metabolized
or burned by the body, cells form byproducts called
free radicals. Free radicals travel through the
cell, disrupting the structure of other molecules
and resulting in cellular damage. Such damage
is believed to contribute to aging and various
health problems.
Antioxidants protect
key cell components from damage by neutralizing
the free radicals. Antioxidants that occur naturally
in the body or are consumed through the diet may
block most of the damage; however, over time,
damaged cells can accumulate and lead to age-related
diseases, researchers say.
"Antioxidant
defense systems limit [free-radical] formation
and scavenge them, but antioxidant defenses are
not 100 percent efficient," said Barry Halliwell,
D.Sc., of the University of London and the University
of California at Davis, speaking at a symposium
sponsored by the International Life Sciences Institute
(ILSI). Over time, "Oxidative stress can
damage proteins, lipids, DNA and carbohydrates."
In an effort to beef
up bodily defenses to combat free-radical activity,
scientists are studying the effects of increasing
individuals' antioxidant levels through the diet
and dietary supplements.

Recent Research
Among the most widely-publicized
research trials on antioxidants was a five-year
study published in the Journal of the National
Cancer Institute involving approximately 30,000
residents of north-central China. Participants
were given either a placebo or a dietary supplement
containing one of seven vitamin-mineral combinations.
Persons who received a daily dose of beta carotene,
vitamin E and selenium had a reduced cancer rate
of 13 percent.
Although many questions
remain as to the significance of these findings
for other populations, the study represents the
first large-scale randomized, prospective, placebo-controlled
study showing the benefits of dietary supplementation
with antioxidant vitamins and minerals. Much of
the previous evidence was based on epidemiological
studies of populations, which suggested an association
between antioxidants and disease prevention but
were not designed to reveal cause and effect relationships.
In another recent
study reported at the American Heart Association
(AHA) Scientific Session in November, women who
consumed high amounts of antioxidant containing
foods had a 33 percent lower risk of heart attack
and a 71 percent lower risk of stroke, than women
who ate few antioxidant-containing foods.
The study involved
1,795 female nurses, each of whom had a history
of heart attack, chest pain due to coronary disease,
or treatment for a blockage in a coronary artery.
Food intake was analyzed according to subjects'
estimated consumption of vitamins C and E, carotene
and riboflavin.
Even after controlling
for other variables that can contribute to cardiovascular
risk such as age and high blood pressure, the
nurses who consumed the most dietary antioxidants
had the greatest disease reduction. Individual
foods most closely associated with the health
benefits included carrots, spinach and other greens.
"These data
suggest that people at high risk because of a
history of cardiovascular disease or events may
benefit the most from increased consumption of
fruits and vegetables," said principal investigator
JoAnn Manson, M.D., of Brigham and Women's Hospital
in Boston.
"These women
were at especially high risk, and any intervention
that impacts on that risk could potentially save
a large number of lives," Manson added. Health
care costs related to cardiovascular disease are
expected to exceed $117.4 billion in 1993 alone,
according to AHA.

Wait and See
Despite these and
other promising findings from antioxidant research
studies, many experts are not yet convinced there
are adequate data to allow a health claim on foods
or dietary supplements. Questions still remain
on issues such as the effectiveness of individual
antioxidant vitamins to prevent which conditions,
their mechanisms of action, optimum levels of
intake and their long-term effects.
Even more contentious
is the issue currently being debated by Congress
and the Food and Drug Administration (FDA) over
whether dietary supplements containing antioxidants
and other compounds should be regulated as foods
or drugs.
Many health groups
such as AHA and the American Cancer Society believe
it is premature to recommend dietary supplements
containing antioxidants, indicating that some
other as yet unidentified substance in fruits
and vegetables may actually be responsible for
reduced disease risk.
"We can't yet
say conclusively that antioxidant vitamins, per
se, as opposed to foods that are high in antioxidants,
can reduce the risk of stroke or heart attack,"
Manson said. "I would support the public
health recommendation for increased fruit and
vegetable consumption among people who at high
risk for cardiovascular disease, as well as for
the general public. But, at this point, I couldn't
recommend that people buy vitamin supplements."
"We're in the
first wave," said Nancy Ernst, M.S., R.D.,
nutritional coordinator at the National Heart,
Lung and Blood Institute who spoke at the ILSI
symposium. "We need to call for more research.
We have a lot of answers but we also have many,
many questions... We've not sufficiently addressed
issues such as other nutritive and nonnutritive
compounds in the diet that may contribute to disease
prevention."
Until further studies
are completed, eating a balanced diet rich in
antioxidant vitamins may be the best way of improving
your health. The following chart outlines foods
high in antioxidants. Resolve to include more
of these foods in your daily diet.

VITAMIN RICH
FOODS
Vitamin A/ liver,
egg yolk, fortified milk, butter, margarine, Beta
Carotene spinach, carrots, squash, broccoli, yams,
tomato, cantaloupe, peaches, fortified grain products,
Vitamin C, citrus fruit and juices (oranges, grapefruit),
strawberries, kiwi, cantaloupe, green peppers,
raw cabbage, spinach, kale, broccoli, Vitamin
E, nuts, seeds, whole grains, vegetable and fish-liver
oils, fortified cereals, dried apricots
Although much of
the scientific community is still calling for
further research on antioxidants before changing
public health recommendations, some consumers
aren't waiting for more data.
According to Catherine
E. Woteki, Ph.D., R.D., of the National Academy
of Sciences, "Data on supplement sources
of nutrient antioxidants show that 36 percent
of adults report using vitamin/mineral supplements.
Food supply data and limited data on intakes and
supplement use indicate that levels of vitamins
E and C and the carotenoids in the diet have increased
among Americans."
Some nutritionists
and policy makers are concerned that individuals
will take excessive amounts of supplements, believing
that if a little bit is good, more must be better.
High doses of some antioxidants can produce adverse
affects in people; for example, excessive vitamin
E can interfere with the action of warfarin, a
blood-thinning medicine often prescribed for patients
with heart disease.
FDA is examining
the scientific data to determine whether there
is adequate scientific data to support a health
claim on antioxidants and disease prevention and
is expected to make a decision sometime next year.
Reprinted from the
International Food Information Council Foundation,
1993